Image display apparatus

ABSTRACT

Provided is an image display apparatus that makes it possible to provide appropriate interaction with a user. The image display apparatus includes: a display displaying a three-dimensional image in such a manner that the three-dimensional object looks as if being in a space defined by a member constituting an external surface and that the three-dimensional object is visible from multiple directions around the display; a motion detector detecting the motion of the display itself caused by an external force; a motion calculation unit calculating the motion of the three-dimensional object caused by the motion of the display itself on the basis of the motion detected by the motion detector on the assumption that the three-dimensional object is actually present in the space; a display control unit changing the three-dimensional image displayed on the display on the basis of the result of calculation by the motion calculation unit; a force sense presentation unit presenting the sense of force to the user of an own apparatus; and a force sense control unit causing the force sense presentation unit to present the sense of force on the basis of the result of calculation by the motion calculation unit.

TECHNICAL FIELD

The technology relates to an image display apparatus.

BACKGROUND

An image display apparatus has been proposed that includes a cylindricalscreen, a substantially circular mirror, and a color projector. Thecylindrical screen and the substantially circular mirror are laminatedon a cylindrical pedestal. The color projector is provided at the centerof the pedestal such that the optical axis is directed vertically upwardto scan laser beams corresponding to RGB colors (see PTL 1, forexample). For the image display apparatus described in PTL 1, the colorprojector outputs laser beams vertically upward in a radial manner, andthe outputted laser beams are reflected from the reflecting mirrortoward the entire circumference of the screen in a radial manner. Thescreen receiving the reflected laser beams on the entire circumferencedisplays a three-dimensional image of the three-dimensional object in aspace defined by the screen. The three-dimensional object is visiblefrom multiple directions around the image display apparatus.

CITATION LIST Patent Literature

[PTL 1] International Publication No. WO 2018/163945

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

Such an image display apparatus has been required not only to display athree-dimensional image but also provide appropriate interaction with auser.

An object of the disclosure is to provide an image display apparatusthat makes it possible to provide more appropriate interaction with auser.

Means for Solving the Problem

An image display apparatus of the disclosure includes: (a) a displaydisplaying a three-dimensional image in such a manner that thethree-dimensional object looks as if being in a space defined by amember constituting an external surface and that the three-dimensionalobject is visible from multiple directions around the display; (b) amotion detector detecting the motion of the display itself caused by anexternal force; (c) a motion calculation unit calculating the motion ofthe three-dimensional object caused by the motion of the display itselfon the basis of the motion detected by the motion detector on theassumption that the three-dimensional object is actually present in thespace; (d) a display control unit changing the three-dimensional imagedisplayed on the display on the basis of the result of calculation bythe motion calculation unit; (e) a force sense presentation unitpresenting the sense of force to the user of an own apparatus; and (f) aforce sense control unit causing the force sense presentation unit topresent the sense of force on the basis of the result of calculation bythe motion calculation unit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an overall configuration of an imagedisplay apparatus according to an embodiment.

FIG. 2 is a diagram illustrating the image display apparatus displayinga three-dimensional image.

FIG. 3 is a diagram illustrating an internal configuration of acontroller.

FIG. 4 is a flowchart illustrating details of control processing.

FIG. 5 is a diagram illustrating an operation of the image displayapparatus according to a modification example.

FIG. 6 is a diagram illustrating an operation of the image displayapparatus according to a modification example.

FIG. 7 is a diagram illustrating an operation the image displayapparatus according to a modification example.

FIG. 8 is a flowchart illustrating details of the control processingaccording to a modification example.

FIG. 9 is a diagram illustrating an operation of the image displayapparatus according to a modification example.

FIG. 10 is a diagram illustrating an operation of an image displayapparatus according to a modification example.

FIG. 11 is a flowchart illustrating details of the control processingaccording to a modification example.

FIG. 12 is a diagram illustrating an operation of an image displayapparatus according to a modification example.

FIG. 13 is a diagram illustrating an operation of the image displayapparatus according to a modification example.

FIG. 14 is a diagram illustrating an overall configuration of the imagedisplay apparatus according to a modification example.

FIG. 15 is a diagram illustrating an overall configuration of the imagedisplay apparatus according to a modification example.

FIG. 16 is a flowchart illustrating details of the control processingaccording to a modification example.

FIG. 17 is a flowchart illustrating details of the control processingaccording to a modification example.

FIG. 18 is a flowchart illustrating details of the control processingaccording to a modification example.

MODES FOR CARRYING OUT THE INVENTION

An exemplary image display apparatus according to an embodiment of thedisclosure will now be described with reference to FIGS. 1 to 18. Theembodiment of the disclosure is described in the order described below.It is to be noted that the disclosure should not be limited to theexamples described below. Additionally, effects described herein aremerely illustrative and not restrictive, and other effects may be made.

1. Embodiment: Image Display Apparatus

-   -   1-1 Overall Configuration of Image Display Apparatus    -   1-2 Details of Control processing    -   1-3 Modification Example

1. Embodiment [1-1 Overall Configuration of Image Display Apparatus]

An image display apparatus 1 according to an embodiment of thedisclosure will now be described. The image display apparatus 1according to the embodiment displays a three-dimensional image of athree-dimensional object 15 in such a manner that the three-dimensionalimage of the three-dimensional object 15 is visible from multipledirections around the three-dimensional image. As illustrated in FIG. 2,the image display apparatus 1 also has a character display function thatdisplays a character as the three-dimensional object 15. The imagedisplay apparatus 1 is small enough to be held in one hand of a user, asillustrated in FIG. 5.

As illustrated in FIG. 1, the image display apparatus 1 according to theimage display apparatus 1 includes a display 2, an input operationdetector 3, a motion detector 4, a sound generator 5, a force sensepresentation unit 6, and a controller 7. In FIG. 1, a pedestal 8 isillustrated as being partially broken to make the interior of thepedestal 8 visible.

The pedestal 8 has an open top side and a closed bottom side. Thedisplay 2 is formed by laminating a cylindrical screen 9 and asubstantially circular reflecting mirror 10 in this order on the opentop side of the pedestal 8.

At the interior center of the pedestal 8, an emitter 12 is provided. Theemitter has an optical axis 11 directed vertically upward. The emitter12 may be, for example, a color projector that scans laser beamscorresponding to RGB colors (hereinafter also referred to as “imagelight 13”) to display pixels. Further, the emitter 12 outputs the imagelight 13 for forming the three-dimensional image radially upward inaccordance with a signal from the controller 7 to cause the outputtedimage light 13 to reflect from the reflecting mirror 10 to the screen 9.The three-dimensional image may be, for example, an image visible as ifthe three-dimensional object 15 were present in a space 14 defined bythe screen 9.

The screen 9 may be, for example, a hologram screen that displays thethree-dimensional image by outputting the incident image light 13 in adiffusional manner. For example, the screen 9 may be a transmissivehologram disclosed in International Publication No. WO 2018/163945 whichis transparent. As illustrated in FIG. 2, the transparent hologramallows the rear side of the image display apparatus 1 to be visible inthe area where the three-dimensional image of the three-dimensionalobject 15 is not displayed. This makes the user feel as if the screen 9were a transparent glass container. In FIG. 2, a tono-sama penguincharacter is illustrated as the three-dimensional object 15.

The reflecting mirror 10 may be a mirror whose bottom surface is areflecting surface from which the image light 13 outputted from theemitter 12 is reflected. The reflecting mirror 10 radially reflects theimage light 13 outputted radially upward from the emitter 12 to theentire circumference of the screen 9.

In the display 2 having the configuration described above, the emitter12 outputs the image light 13 radially upward in accordance with thesignal from the controller 7 as illustrated in FIG. 1, and the outputtedimage light 13 is radially reflected by the reflecting mirror 10 to theentire circumference of the screen 9. When the reflected image light 13reaches the entire circumference of the screen 9, the three-dimensionalimage visible as if being present in the space 14 defined by the screen9 is displayed and in such a manner that the three-dimensional image isvisible from multiple directions around the image display apparatus 1,as illustrated in FIG. 2. This makes the user feel as if the screen 9were a transparent container made of glass or the like and thethree-dimensional object 15 were accommodated in the container.Accordingly, it is possible to display a three-dimensional image withoutusing a special device such as a head mounted display that bothers theuser when mounting.

It is to be noted that although the space 14 is a space defined by thescreen 9 having a cylindrical shape in the embodiment, anotherconfiguration may be employed. The space 14 only has to be a spacedefined by a member that constitutes an external surface protrudingoutward. The space 14 may be, for example, a space defined by the screen9 having a semi-cylindrical shape or a square tubular shape.

The input operation detector 3 detects an operation input performed bythe user. The input operation detector 3 outputs a detection result tothe controller 7. The input operation detector 3 may be, for example, atleast one of a touch panel that is provided on the external surface ofthe display 2, a microphone that picks up surrounding sounds of thedisplay 2, a camera that captures surrounding images of the display 2,or a distance image sensor that captures surrounding distance images ofthe display 2 (e.g., a time of flight (TOF) camera). In the followingdescription of the embodiment, the input operation detector 3 is a touchpanel, and the “input operation detector 3” is thus also referred to asa “touch panel 3”. The touch panel 3 is provided on the entire outercircumference of the screen 9 and detects the presence or absence of afinger or the like in contact with the touch panel 3 and the coordinatesof the contact position. The touch panel 3 may be operable by aplurality of operation methods, including a flick operation and apointing operation.

The motion detector 4 is provided inside the pedestal 8, and detects themotions of the display 2 itself caused by an external force. Theexternal force may be, for example, a force shaking the display 2 up anddown in the directions parallel to the optical axis 11. The motions ofthe display 2 itself may be, for example, upward and downward motions ofthe display 2. Data on the motions is outputted to the controller 7. Themotion detector 4 may be, for example, an acceleration sensor thatdetects acceleration rates in three-directions, i.e., X, Y, and Zdirections. In a case where the motion detector 4 is the accelerationsensor, the data on the motions may be the acceleration rates.

The sound generator 5 is provided inside the pedestal 8, and outputssounds or the like in association with motions of the three-dimensionalobject 15 to the surroundings of the display 2 in accordance withsignals from the controller 7. The sound generator 5 may be, forexample, an omnidirectional speaker (i.e., 360° speaker).

The force sense presentation unit 6 is provided inside the pedestal 8,and presents the user of the image display apparatus 1 (own apparatus)senses of force or the like in association with the motions of thethree-dimensional object 15 in accordance with signals from thecontroller 7. The force sense presentation unit 6 may be, for example, aforce sense presentation device that generates a force having a desiredmagnitude, a force directed in a desired direction, and a rotationalforce, by controlling the angular momenta of a plurality of rotors. Forexample, a hybrid interface disclosed in Japanese Unexamined PatentApplication Publication No. 2005-190465 may be provided by controllingthe rotational directions, the rotation speeds, and the phases of twoeccentric rotors. The hybrid interface presents a vibration with adesired direction, a desired intensity, and a desired frequency, arotational force, and a sense of force. According to the hybridinterface, the phases of the two eccentric rotors are controlled byrotating the eccentric rotors in opposite directions in a synchronizedmanner, to synthesize a force in linear simple harmonic motion in adesired direction. This enables presentation of the sense of shock at acollision.

The controller 7 is provided inside the pedestal 8, and provided withhardware sources such as a storage device 16 and a processor 17, asillustrated in FIG. 3.

The storage device 16 stores a control program for controlling the imagedisplay apparatus 1. The control program is executable by the processor17. The storage device 16 also stores various pieces of data necessaryfor the execution of the control program.

The processor 17 implements a display control unit 18, a mode switchingunit 19, a motion calculation unit 20, a force sense control unit 21,and a sound control unit 22 in accordance with the control programstored in the storage device 16. Additionally, the processor 17 causesthe display control unit 18, the mode switching unit 19, the motioncalculation unit 20, the force sense control unit 21, and the soundcontrol unit 22 to output signals for respectively controlling the imagelight 13, the sound, and the sense of force to the emitter 12, the soundgenerator 5, and the force sense presentation unit 6 on the basis of themotion data regarding the display 2 itself outputted from the motiondetector 4. The processor 17 thereby executes control processing forfacilitating the interaction between the user and the image displayapparatus 1. The display control unit 18 includes a display operationunit 23.

[1-2 Details of Control Processing]

The control processing executed by the display control unit 18, the modeswitching unit 19, the motion calculation unit 20, the force sensecontrol unit 21, and the sound control unit 22 that are implemented bythe processor 17 will now be described. The control processing isexecuted when a non-illustrated power switch of the image displayapparatus 1 is turned on.

First, as illustrated in Step S101 of FIG. 4, the display control unit18 outputs a signal for causing the display 2 to output the image light13 for displaying a three-dimensional image to the emitter 12. At thistime, the three-dimensional object 15 is displayed at a central area ofthe space 14 without being in contact with the top and bottom ends ofthe space 14, so that the bottom face of the three-dimensional object 15is visible for the user. This makes the user feel as if thethree-dimensional object 15 were floating in the space 14.

Thereafter, the processing proceeds to Step S102 in which the modeswitching unit 19 determines whether the display 2 is held in the handof the user. Specifically, the detection result outputted from the touchpanel 3 is acquired first. Thereafter, it is determined whether the palmor fingers are in contact with the touch panel 3 on the basis of theacquired detection result (e.g., information on the coordinates ofcontact positions of the fingers or the like). If it is not determinedthat the fingers or the like are in contact with the touch panel 3, thedisplay 2 is determined not to be held in the hand of the user (No), andthe processing proceeds to Step S103. In contrast, if it is determinedthat the fingers or the like are in contact with the touch panel 3, thedisplay 2 is determined to be held in the hand of the user (Yes), andthe processing proceeds to Step S104.

In Step S103, the mode switching unit 19 switches the mode of the imagedisplay apparatus 1 to a “placed mode”. In the “placed mode”, thedisplay operation unit 23 outputs a signal for changing thethree-dimensional image displayed on the display 2 on the basis of aflick operation or a pointing operation performed on the touch panel 3to the emitter 12. Specifically, the detection result outputted from thetouch panel 3 is acquired first. Thereafter, it is determined whether aflick operation or a pointing operation has been performed on the basisof the acquired detection result. Then, if it is determined that a flickoperation has been performed, image data on the three-dimensional imagefor rotating the three-dimensional object 15 in the direction of theflick operation are sequentially generated. If it is determined that atouch operation is performed while the three-dimensional object 15 isrotating, image data on the three-dimensional image for stopping therotation of the three-dimensional object 15 are generated.

In contrast, if it is determined that a pointing operation has beenperformed, the display operation unit 23 sequentially generates imagedata on the three-dimensional image for causing the three-dimensionalobject 15 to perform an operation corresponding to the positionspecified by the pointing operation. At the same time, the generatedimage data are sequentially converted into data of the image light 13,and signals for causing emission of the image light 13 indicated by thedata acquired as the result of conversion are sequentially outputted tothe emitter 12. This flow including generating the image data on thethree-dimensional image, converting into the data of the image light 13,and outputting the signals to the emitter 12 is repeated until thedisplay 2 is held in the hand. When the display 2 is held in the hand,the processing returns to Step S102. At this time, the three-dimensionalobject 15 is kept displayed at the central area of the space 14 of thedisplay 2 without being in contact with the top and bottom ends of thespace 14. This makes the user feel as if the three-dimensional object 15were floating in the space 14.

In Step S104, the mode switching unit 19 determines whether the display2 is held and shaken in the hand of the user. Specifically, the motiondata outputted from the motion detector 4 is acquired first. Thereafter,it is determined whether the magnitude of the vibration of the display 2is greater than or equal to a predetermined threshold on the basis ofthe acquired data. Then, if it is determined that the magnitude of thevibration of the display 2 is less than the predetermined threshold, thedisplay 2 is not determined to be held in the hand (No), and theprocessing proceeds to Step S105. In contrast, if it is determined thatthe magnitude of the vibration of the display 2 is greater than or equalto the predetermined threshold, the display 2 is determined to be heldin the hand (Yes), and the processing proceeds to Step S106.

In Step S105, the mode switching unit 19 switches the mode of the imagedisplay apparatus 1 to a “held mode”. In the “held mode”, the displayoperation unit 23 outputs a signal for changing the three-dimensionalimage displayed on the display 2 to the emitter 12 on the basis of aflick operation performed on the touch panel 3. Specifically, thedetection result outputted from the touch panel 3 is acquired first.Thereafter, it is determined whether a flick operation has beenperformed on the basis of the acquired detection result. Then, if it isdetermined that a flick operation has been performed, image data on thethree-dimensional image for rotating the three-dimensional object 15 inthe direction of the flick operation are sequentially generated. At thesame time, the generated image data are sequentially converted into dataof the image light 13, and signals for causing emission of the imagelight 13 indicated by the data acquired as the result of conversion aresequentially outputted to the emitter 12. That is, when the display 2 isheld in the hand, the display operation unit 23 changes thethree-dimensional image displayed on the display 2 only on the basis ofthe detection result of an input operation performed by one (a flickoperation) of the operation methods of the touch panel 3. Accordingly,unlike in the case of the “placed mode” in Step S103, only a flickoperation is accepted and a pointing operation is not accepted in the“held mode”.

This flow including generating the image data on the three-dimensionalimage, converting into the data of the image light 13, and outputtingthe signals to the emitter 12 is repeated until the display 2 is placedor shaken. When the display 2 is placed or shaken, the processingreturns to Step S102. At this time, the three-dimensional object 15 iskept displayed at the central area of the space 14 without being incontact with the top and bottom ends of the space 14. This makes theuser feel as if the three-dimensional object 15 were floating in thespace 14.

It is to be noted that although the image data on the three-dimensionalimage for rotating the three-dimensional object 15 in the direction ofthe flick operation are sequentially generated in Step S105 in theembodiment, another configuration may be employed. For example, it maybe determined whether it is immediately after the display 2 is held inthe user, i.e., whether it is immediately after the switching of thedetermination in Step S102 from “No” to “Yes”. If it is determined thatit is immediately after the switching, the image data on thethree-dimensional image for indicating the three-dimensional object 15(e.g., the tono-sama penguin character) in a surprised state aresequentially generated.

In Step S106, in contrast, the mode switching unit 19 switches the modeof the image display apparatus 1 to a “shaken mode”. In the “shakenmode”, the motion calculation unit 20 calculates the motion of thethree-dimensional object 15 caused by the motion of the display 2 itselfon the assumption that the three-dimensional object 15 is actuallypresent in the space 14 of the display 2. Specifically, the motion ofthe three-dimensional object 15 at the time when the display 2 performsthe motion indicated by the data is calculated on the basis of themotion data acquired in Step S104 and substance data of thethree-dimensional object 15 in accordance with a predetermined physicallaw. The substance data of the three-dimensional object 15 may be, forexample, the mass, center of gravity, density, volume, Young's modulus,Poisson's ratio, vibration damping rate, viscosity, and outer shape ofthe three-dimensional object 15. Additionally, the predeterminedphysical law may be, for example, the law of inertia, the law of motion,the law of action and reaction, the law of conservation of energy, thelaw of universal gravitation, or the Newton's law of viscosity. Themotion of the three-dimensional object 15 may be, for example, theposition, the moving speed, the presence or absence of a collision withthe top or bottom end of the space 14, or the bouncing speed after thecollision of the three-dimensional object 15.

Accordingly, when the display 2 held in the hand of the user is swungdown in such a condition that the optical axis 11 of the display 2 isdirected in the vertical direction, for example, the motions of thethree-dimensional object 15 including an upward motion of thethree-dimensional object 15 in the space 14, a collision of thethree-dimensional object 15 with the top end of the space 14 due to theinertia, and a bouncing motion of the three-dimensional object caused bythe shock of the collision are calculated. When the display 2 is swungup afterward in such a condition that the optical axis 11 of the display2 is directed in the vertical direction, for example, the motions of thethree-dimensional object 15 including a downward motion of thethree-dimensional object 15 in the space 14 due to the inertia, acollision of the three-dimensional object 15 with the bottom end of thespace 14, and a bouncing motion of the three-dimensional object 15caused by the shock of the collision are calculated. Accordingly, whenthe swinging up and down operations of the display 2 held in the handare repeated, the above-described calculations of the motions of thethree-dimensional object 15 are repeated.

At the same time, the display control unit 18 outputs a signal forchanging the three-dimensional image on the basis of the result ofcalculation by the motion calculation unit 20 to the emitter 12.Specifically, the image data on the three-dimensional image aresequentially generated in accordance with the calculated motions of thethree-dimensional object 15 so that the motions of the three-dimensionalobject 15 caused by the motions of the display 2 itself are displayed.If it is determined that the three-dimensional object 15 will collidewith the top or bottom end of the space 14 as the result of thecalculation, the image data on the three-dimensional image representingthe three-dimensional object 15 colliding with the top or bottom end ofthe space 14 are generated. At the same time, the generated image dataare sequentially converted into data of the image light 13, and signalsfor causing emission of the image light 13 indicated by the dataacquired as the result of conversion are sequentially outputted to theemitter 12. Accordingly, unlike in the case of Steps S103 and S105, onlythe shaking operation on the display 2 held in the hand is accepted, anda flick operation and a pointing operation are not accepted. That is,when the display 2 held in the hand is shaken, the display control unit18 prohibits the three-dimensional image from changing on the basis ofthe result of detection by the touch panel 3.

Accordingly, when swinging up and down operations of the display 2 heldin the hand of the user are repeated, the display 2 repeatedly displaysthe three-dimensional images representing the three-dimensional object15 moving upward in the space 14 to collide with the top end of thespace 14 and moving downward in the space 14 to collide with the bottomend of the space 14. That is, unlike in the case of Steps S101, S103,and S105, the three-dimensional object 15 is not kept floating in theair, but is brought into the state based on the result of calculation bythe motion calculation unit 20.

In this case, the sound control unit 22 outputs a signal for generatinga sound on the basis of the result of calculation by the motioncalculation unit 20 to the sound generator 5. Specifically, a signal forgenerating a sound (e.g., a collision sound or a voice “Stop!”) inaccordance with the motion of the three-dimensional object 15 acquiredas the result of the calculation is outputted to the sound generator 5,so that the sound of the three-dimensional object 15 is generated on thebasis of the motion of the display 2 itself. The method of calculatingthe collision sound may be, for example, the method described inJapanese Unexamined Patent Application Publication No. 2009-205626.Japanese Unexamined Patent Application Publication No. 2009-205626describes the method using a 3D model of the three-dimensional object 15and the physical property such as the hardness of the three-dimensionalobject 15.

At the same time, the force sense control unit 21 outputs a signal forpresenting the sense of force based on the result of calculation by themotion calculation unit 20 to the force sense presentation unit 6.Specifically, the force sense control unit 21 outputs, to the forcesense presentation unit 6, a signal for presenting the sense of force inaccordance with the motion of the three-dimensional object 15 calculatedon the assumption that the three-dimensional object 15 (e.g., thetono-sama penguin character) is actually present in the space 14. Thismakes the user of the image display apparatus 1 (the own apparatus) feelthe vibration supposed to be generated when the three-dimensional object15 comes into contact with the member (e.g., the pedestal 8, the screen9, or the reflecting mirror 10) constituting the external surface of thespace 14.

The flow including generating the image data on the three-dimensionalimage, converting into the data of the image light 13, and outputtingthe signals to the emitter 12, and the flow including outputting to thesound generator 5 and the force sense presentation unit 6 are repeateduntil the shaking operation of the display 2 is stopped. When theshaking operation is stopped, the processing returns to Step S102.

It is to be noted that although the image display apparatus 1 accordingto the embodiment has the character display function of displaying thetono-sama penguin character as the three-dimensional object 15 asillustrated in FIG. 2, another configuration may be employed. Forexample, the image display apparatus 1 may have a product displayfunction of displaying a commercial product from a shopping site as thethree-dimensional object 15, as illustrated in FIG. 5. FIG. 5illustrates the image display apparatus 1 displaying a fountain pen thatis a commercial product from a shopping site as the three-dimensionalobject 15. It is to be noted that, in a case where an item such as afountain pen is used as the three-dimensional object 15, thethree-dimensional image representing how the item is broken may bedisplayed on the basis of the speed or the acceleration rate of theshaking operation on the display 2, unlike in the case where a characteris used as the three-dimensional object 15.

Alternatively, as illustrated in FIG. 6, for example, the image displayapparatus 1 may have a musical instrument function of causing thethree-dimensional object 15 to serve as a musical instrument when theimage display apparatus 1 is used for a musical performance. FIG. 6illustrates the image display apparatus 1 displaying a handbell that isone example of musical instruments as the three-dimensional object 15.

As described above, the image display apparatus 1 according to theembodiment of the disclosure calculates the motions of thethree-dimensional object 15 caused by the motions of the display 2itself on the assumption that the three-dimensional object 15 isactually present in the space 14. Further, the three-dimensional imagedisplayed on the display 2 is changed on the basis of the calculatedmotion of the three-dimensional object 15. Additionally, the force sensepresentation unit 6 presents the sense of force on the basis of thecalculated motion of the three-dimensional object 15. Accordingly, whenthe display 2 held in the hand is swung up and down, for example, thethree-dimensional images and the senses of force representing themotions of the three-dimensional object 15 (e.g., the tono-sama penguin,fountain pen, or handbell) are provided in association with the upwardand downward motions of the space 14. This makes the user instinctivelyrecognize the weight, hardness, or the like of the three-dimensionalobject 15. Accordingly, it is possible to provide the image displayapparatus 1 that makes it possible to provide more appropriateinteraction with a user.

Further, the image display apparatus 1 according to the embodiment ofthe disclosure changes the three-dimensional image on the basis of thecalculated motion of the three-dimensional object 15 so that the motionof the three-dimensional object 15 caused by the display 2 itself isdisplayed. Additionally, the force sense presentation unit 6 presentsthe sense of force on the basis of the motion of the three-dimensionalobject 15 calculated on the assumption that the three-dimensional object15 is actually present in the space 14. This makes the user feel thevibration supposed to be generated when the three-dimensional object 15comes into contact with the member constituting the external surface.Accordingly, it is possible to provide the sense of force supposed to begenerated on the assumption that the three-dimensional object 15 comesinto contact with the pedestal 8, the screen 9, or the reflecting mirror10. This makes the user feel as if the three-dimensional object 15 werepresent in the space 14.

Further, the image display apparatus 1 according to the embodiment ofthe disclosure calculates the motion of the three-dimensional object 15on the basis of the substance data of the three-dimensional object 15(e.g., at least one of the mass, center of gravity, density, volume,Young's modulus, Poisson's ratio, vibration damping rate, viscosity, orouter shape) and the motion detected by the motion detector 4.Accordingly, when a commercial product (e.g., a fountain pen) from ashopping site is displayed as the three-dimensional object 15 asillustrated in FIG. 5, for example, the three-dimensional image and thesense of force are provided that accurately represent the mass or thelike of the commercial product (e.g., the fountain pen), making the userinstinctively recognize the weight, hardness, or the like of thecommercial product (e.g., the fountain pen). This is effective for theuser (i.e., purchaser) who wants to know the physical properties of thecommercial product before purchase. This also decreases in returns ofproducts, resulting in a cost reduction for stores. Such a decrease inreturns of products also reduces the transport loads on forwardingagencies.

Further, the image display apparatus 1 according to the embodiment ofthe disclosure changes the three-dimensional image displayed on thedisplay 2 on the basis of the result of detection of the input operationby the input operation detector 3. This allows the three-dimensionalobject 15 to rotate in a direction desired by the user, for example.

Further, the input operation detector 3 in the image display apparatus 1according to the embodiment of the disclosure is at least one of a touchpanel that is provided on the external surface of the display 2, amicrophone that picks up surrounding sounds of the display 2, a camerathat captures surrounding images of the display 2, or a distance imagesensor that captures surrounding distance images of the display 2. Thisallows various input operations to be performed, such as a touchingoperation of fingers, a sound operation, and a gesture operation.

Further, according to the image display apparatus 1 of the embodiment ofthe disclosure, the single input operation detector 3 is operable by aplurality of operation methods. While the display 2 is held in the hand,the three-dimensional image displayed on the display 2 is changed onlyon the basis of the result of detection of an input operation performedby one of the operation methods. Accordingly, when the user holds thedisplay 2 with the hand to view the three-dimensional object 15 from alldirections of 360°, for example, only flick operations are accepted.This prevents the three-dimensional object from changing in response toa pointing operation that the user unintentionally performed on theinput operation detector 3. It is thus possible to prevent thethree-dimensional object 15 from making unintended motions.

Additionally, according to the image display apparatus 1 of theembodiment of the disclosure, while the display 2 held in the hand isshaken, the three-dimensional image is prohibited from changing on thebasis of the result of detection by the input operation detector 3.Accordingly, it is possible to more certainly prevent thethree-dimensional object 15 from making unintended motions.

[1-3 Modification Examples]

(1) Although the display 2 is shaken in the directions parallel to theoptical axis 11 in the embodiment, another configuration may beemployed. For example, the display 2 may be shaken in directionscrossing the optical axis as illustrated in FIG. 7. In FIG. 7, a toyhaving a large ring connected with small rings is displayed as thethree-dimensional object 15.

(2) Further, although the display control unit 18 changes thethree-dimensional image displayed on the display 2 only on the basis ofthe result of detection of an input operation performed by one of theoperation methods in the “held” mode in the embodiment, anotherconfiguration may be employed. For example, the three-dimensional imagedisplayed on the display 2 may be changed only on the basis of theresult of detection of an input operation with the highest priority bythe input operation detector 3.

In such a configuration, when input operations performed by someoperation methods (e.g., a flick operation operation and a pointingoperation) are detected, the display control unit 18 may change thethree-dimensional image displayed on the display 2 only on the basis ofan input operation performed by an operation method with the highestpriority (e.g., the flick operation), for example. Further, thepriorities assigned to the operation methods may differ between when thedisplay 2 is shaken (Step S104 “Yes” in FIG. 4) and when the display 2is not shaken (Step S104 “No” in FIG. 4). For example, when the display2 is not shaken, the priority of the flick operation may be set higherthan the priority of the pointing operation, whereas when the display 2is shaken, the priority of the pointing operation may be set higher thanthe priority of the flick operation.

According to the image display apparatus 1 of the modification exampleas described above, when input operations performed by some operationmethods are detected, the three-dimensional image displayed on thedisplay 2 is changed only on the basis of the input operation performedby the operation method with the highest priority. Additionally, thepriorities assigned to the operation methods differ between when thedisplay 2 is shaken and when the display 2 is not shaken. Accordingly,even when an input operation is mistakenly performed by an operationmethod with a low priority together with an operation input performed byan operation method with a high priority, for example, only the inputoperation performed by the operation method with the high priority isvalid, and the input operation performed by the operation method withthe low priority is invalid. This prevents an unintended operation frombeing performed.

(3) Further, although the image display apparatus 1 has the characterdisplay function or the product display function in the embodiment,another configuration may be employed. For example, the image displayapparatus 1 may have a learning assist function of representingbehaviors of the three-dimensional object 15 at the time when thesubstance data on the substance constituting the three-dimensionalobject 15 (e.g., the viscosity of a liquid) is changed. In a case wherethe image display apparatus 1 has the learning assist function, StepS105 of the control processing illustrated in FIG. 4 may be replacedwith Step S201 in the “held mode”, as illustrated in FIG. 8, forexample. Further, in the following description of the modificationexample, the substance constituting the three-dimensional object 15 is aliquid, as illustrated in FIG. 9, and the “three-dimensional object 15”is thus also referred to as a “liquid 15”.

In Step S201, the motion calculation unit 20 calculates the motion ofthe liquid 15 caused by the motion of the display 2 itself on theassumption that the liquid 15 is actually present in the space 14 of thedisplay 2. Specifically, the motion of the liquid 15 at the time whenthe display 2 performs the motion indicated by the data is calculated onthe basis of the motion data acquired in Step S104 and the substancedata on the liquid 15 in accordance with the predetermined physical law.Accordingly, when the display 2 held in the hand and tilted such thatthe longitudinal direction is directed to the right direction, forexample, the motions of the liquid 15 including a rightward motion ofthe liquid 15 in the space 14 due to the gravity, a collision of theliquid 15 with the right end of the space 14, and a bouncing motion ofthe liquid 15 caused by the shock of the collision are calculated.Thereafter, when the display 2 held in the hand and tilted such that thelongitudinal direction is directed to the left direction, the motions ofthe liquid 15 including a leftward motion of the liquid 15 in the space14 due to the gravity, a collision of the liquid 15 with the left end ofthe space 14, and a bouncing motion of the liquid 15 caused by the shockof the collision are calculated. Accordingly, when operations fortilting the display 2 held in the hand to the right and left arerepeated, the calculation of the motions of the liquid 15 describedabove are repeated.

At the same time, the display control unit 18 outputs a signal forchanging the three-dimensional image on the basis of the result ofcalculation by the motion calculation unit 20 to the emitter 12.Specifically, the image data on the three-dimensional image inaccordance with the motion of the liquid 15 acquired as the result ofthe calculation are sequentially generated so that the motion of theliquid 15 caused by the motion of the display 2 itself is displayed. Atthe same time, the generated image data are sequentially converted intothe data on the image light 13, and signals for causing emission of theimage light 13 indicated by the data acquired as the result ofconversion are sequentially outputted to the emitter 12.

Accordingly, when the operations for tilting the display 2 held in thehand of the user to the right and left are repeated, thethree-dimensional images representing the liquid 15 moving rightward inthe space 14 to collide with the right end of the space 14 and movingleftward in the space 14 to collide with the left end of the space 14are repeatedly displayed. That is, the state of the liquid 15 is decidedon the basis of the result of calculation by the motion calculation unit20.

The motion of the liquid 15 is calculated using a predetermined physicallaw, such as the Newton's law of viscosity. Thus, in a case where theliquid 15 is a fluid having a high viscosity, such as starch syrup, thethree-dimensional image representing the liquid 15 deforming slowly isdisplayed. In a case where the liquid 15 is a fluid having a lowviscosity, in contrast, the three-dimensional image representing theliquid 15 deforming quickly is displayed.

At the same time, the sound control unit 22 outputs a signal forgenerating a sound on the basis of the result of calculation by themotion calculation unit 20 to the sound generator 5. Specifically, thesound control unit 22 outputs, to the sound generator 5, a signal forgenerating a sound in accordance with the motion of the liquid 15acquired as the result of the calculation so that a sound of the liquid15 caused by the motion of the display 2 itself is generated. The soundin accordance with the motion of the liquid 15 may be, for example, acollision sound or a wave sound.

Further, the force sense control unit 21 outputs a signal for presentingthe sense of force based on the result of calculation by the motioncalculation unit 20 to the force sense presentation unit 6.Specifically, the force sense control unit 21 outputs, to the forcesense presentation unit 6, a signal for presenting the sense of force inaccordance with the motion of the liquid 15 calculated on the assumptionthat the liquid 15 is actually present in the space 14. This makes theuser of the image display apparatus 1 (the own apparatus) feel thevibration supposed to be generated when the liquid 15 comes into contactwith the member constituting the external surface of the space 14 (e.g.,the pedestal 8, the screen 9, or the reflecting mirror 10).

These signals are repeatedly outputted to the emitter 12, the soundgenerator 5, and the force sense presentation unit 6 until the display 2is placed or shaken. When the display 2 is placed or shaken, theprocessing returns to Step S102.

As described above, the image display apparatus 1 according to themodification example calculates the motion of the three-dimensionalobject 15 so that the three-dimensional object 15 moving on the basis ofthe substance data of the three-dimensional object 15 and the motiondetected by the motion detector 4 in accordance with the predeterminedphysical law is displayed. Accordingly, when the liquid having apredetermined viscosity is displayed as the three-dimensional object 15as illustrated in FIG. 9, for example, the three-dimensional imagerepresenting the flow of the liquid depending on the viscosity and thesense of force in association with the motion of the liquid arepresented. This helps a user who learns the viscosity.

It is to be noted that although the display 2 is tilted to the right orleft by the user in the modification example, another configuration maybe employed. For example, the display 2 may be turned upside down.

Further, although the processing proceeds to Step S201 of FIG. 8 whenthe display 2 is held in the hand of the user and is not shaken as inSteps S102 and S104 of FIG. 8 in the modification example, anotherconfiguration may be employed. For example, when the substance data(e.g., the viscosity) of the three-dimensional object 15 is set usinganother device such as a smartphone, the processing may proceed to StepS201 of FIG. 8. In this configuration, when the setting of the substancedata of the three-dimensional object 15 is erased (initialized) usingthe other device, Step S201 of FIG. 8 may be stopped repeating and theprocessing may return to Step S102.

Further, although the behaviors of the liquid 15 are displayed with thelearning assist function as illustrated in FIG. 9 in the modificationexample, another configuration may be employed. For example, asillustrated in FIG. 10, a creature illustrated on an opened page of apicture book may be displayed in cooperation with the picture book. FIG.10 illustrates the image display apparatus 1 displaying a butterfly asthe three-dimensional object 15.

(4) Further, the image display apparatus 1 may have a motion displayfunction of displaying the result of simulation of motion of a snowglobe at the time when the display 2 is tapped by a finger, for example.In a case where the image display apparatus 1 has the motion displayfunction, Step S105 of the control processing illustrated in FIG. 4 maybe replaced with Step S301 in the “held mode”, as illustrated in FIG.11, for example. Further, in the following description of themodification example, the three-dimensional object 15 is snow asillustrated in FIG. 12, and the “three-dimensional object 15” is thusalso referred to as “snow 15”.

In Step S301, the motion calculation unit 20 calculates the motion ofthe snow 15 caused by the motion of the display 2 itself on theassumption that the snow 15 is actually present in the space 14 of thedisplay 2. Specifically, the position of the touch panel 3 in contactwith a finger is detected on the basis of the result of detectionacquired from the touch panel 3. Thereafter, the motions of the snow 15at the time when the touch panel 3 is tapped by the finger at a portionin contact with the finger and when the display 2 performs the motionindicated by the data are calculated on the basis of the detectedposition, the motion data acquired in Step S104, and the substance dataof the snow 15 in accordance with a predetermined physical law.Accordingly, when the display 2 is tapped by the finger of the user, forexample, the motions of the snow 15 including blowing up of the snow 15from the tapped portion and piling up of the snow 15 are calculated. Inthis case, the amount of the snow 15 blowing up increases as the motionof the display 2 itself becomes larger.

Further, the display control unit 18 outputs a signal for changing thethree-dimensional image on the basis of the result of calculation by themotion calculation unit 20 to the emitter 12. Specifically, the imagedata on the three-dimensional image in accordance with the motion of thesnow 15 acquired as the result of the calculation are sequentiallygenerated so that the motion of the snow 15 caused by the motion of thedisplay 2 itself is displayed. At the same time, the generated imagedata are sequentially converted into the data on the image light 13, andsignals for causing emission of the image light 13 indicated by the dataacquired as the result of conversion are sequentially outputted to theemitter 12.

Accordingly, when the display 2 is tapped by the user, thethree-dimensional image representing the snow 15 blowing up in the space14 due to a vibration caused by the tapping is displayed on the display2.

At the same time, the sound control unit 22 outputs a signal forgenerating a sound on the basis of the result of calculation by themotion calculation unit 20 to the sound generator 5. Specifically, thesound control unit 22 outputs, to the sound generator 5, a signal forgenerating a sound in accordance with the motion of the snow 15 acquiredas the result of the calculation so that a sound of the snow 15 (e.g., asound of the snow 15 blowing up or piling up) caused by the motion ofthe display 2 itself is generated.

At the same time, the force sense control unit 21 outputs a signal forpresenting the sense of force based on the result of calculation by themotion calculation unit 20 to the force sense presentation unit 6.Specifically, the force sense control unit 21 outputs, to the forcesense presentation unit 6, a signal for presenting the sense of force inaccordance with the motion of the snow 15 calculated on the assumptionthat the snow 15 is actually present in the space 14. This makes theuser of the image display apparatus 1 (the own apparatus) feel thevibration supposed to be generated when the snow 15 comes into contactwith the member constituting the external surface of the space 14 (e.g.,the pedestal 8, the screen 9, or the reflecting mirror 10).

These signals are repeatedly outputted to the emitter 12, the soundgenerator 5, and the force sense presentation unit 6 until the display 2is placed or shaken. When the display 2 is placed or shaken, theprocessing returns to Step S102.

Note that, although the three-dimensional image representing the snow 15blowing up is displayed when the display 2 is tapped by a finger in themodification example, another configuration may be employed. Forexample, the three-dimensional image representing the snow 15 blowing upmay be displayed when another operation is performed, such as when thedisplay 2 is tilted, when the display 2 is blown by a blast of air, whena portion of the image display apparatus 1 is flipped by a finger, orwhen a physical force is exerted on the image display apparatus 1.

Additionally, when the display 2 is tapped, for example, thethree-dimensional image of an object of various kinds, such as a snowflower or a snow fairy may be displayed at the tapped position.

As described above, the image display apparatus 1 according to themodification example detects the position of the touch panel 3 incontact with a finger, and changes the three-dimensional image displayedon the display 2 on the basis of the detected position. Accordingly,when snow is displayed as the three-dimensional object 15 as illustratedin FIG. 12, for example, it is possible to provide the three-dimensionalimage of the snow blowing up from the tapped position and the sense offorce in association with the blowing snow. This reproduces a snow globemore appropriately.

(5) Further, the image display apparatus 1 may be used when the userwant to see current conditions of a distant area, for example: The imagedisplay apparatus 1 may have an actual-space cutting-out displayfunction of displaying live camera images captured by a drone hoveringover the distant area. The drone hovering over a distant area may be,for example, a submarine drone moving in a coral sea, as illustrated inFIG. 13. When the image display apparatus 1 having the actual-spacecutting-out display function is moved in parallel, the location imagedby the submarine drone may be shifted in the same direction by the samedistance. This allows the image display apparatus 1 to display thethree-dimensional image of a desired location in the sea.

(6) Further, although the controller 7 is provided inside the pedestal 8to be integrated with the display 2 in the embodiment, anotherconfiguration may be employed. For example, the controller 7 may beprovided outside the pedestal 8 to be separated from the display 2.Separating the controller 7 from the display 2 allows the controller 7to have a larger size.

(7) Further, although the three-dimensional image is displayed byemitting the image light 13 to the cylindrical screen 9 in theembodiment, another configuration may be employed. For example, thethree-dimensional image is displayed on an cubic apparatus provided witha liquid crystal display on each face, for example.

(8) Further, although the display 2 displays the three-dimensional imageviewable from all directions of 360° around the display 2 in theembodiment, another configuration may be employed. For example, thethree-dimensional image may be viewable within an angular range lessthan 360°.

(9) Further, although the force sense presentation unit 6 is the forcesense presentation device that displays the sense of force bycontrolling the angular momenta of the rotors in the embodiment, anotherconfiguration may be employed. For example, a linear actuator may beused that presents the sense of force by generating vibrations. In thiscase, the force sense presentation units 6 may be respectively providedinside the pedestal 8 and the reflecting mirror 10, as illustrated inFIG. 14. Providing the respective force sense presentation units 6inside the pedestal 8 and the reflecting mirror 10 makes it possible topresent a more realistic sense of force using vibrations.

Further, in a case of the force sense presentation unit 6 presenting thesense of force using vibrations, a plurality of the force sensepresentation units 6 each in a linear shape may be provided on theexternal surface of the display 2, as illustrated in FIG. 15, forexample. The liner force sense presentation unit 6 may be, for example,a linear actuator that generates a vibration at a desired position outof a plurality of positions defined on (the line of) the force sensepresentation unit 6. With the configuration in which the plurality oflinear force sense presentation units 6 are provided, it is possible togenerate a vibration at a position of the screen 9 where thethree-dimensional object 15 collides, as illustrated in FIG. 7.Additionally, it is possible to reproduce the propagation of thevibration generated at the collision position along the external surfaceof the display 2. This achieves more realistic presentation of the senseof force.

(10) Further, although any one of the “placed mode”, the “held mode”,and the “shaken mode” is selected on the basis of the result ofdetermination as to whether the display 2 is held in the hand of theuser and whether the display 2 is shaken as in Steps S102 and S104 ofFIG. 4 in the embodiment, another configuration may be employed. Forexample, the “held mode” may be switched to the “placed mode” when it isdetermined that no contact of fingers or a palm with the image displayapparatus 1 is detected and that no upward nor downward motion(displacement) of the display 2 is detected. Specifically, the modeswitching unit 19 determines whether contact of fingers or a palm withthe touch panel 3 is detected on the basis of the detection resultoutputted from the touch panel 3, as illustrated in FIG. 16 (Step S401).Thereafter, if it is determined that no contact is detected, it isdetermined whether requirements that the bottom face of the imagedisplay apparatus 1 is kept horizontal and that display 2 is not movedin any direction are satisfied on the basis of the detection resultsoutputted from a non-illustrated gyroscope sensor and the motiondetector 4 (Step S402). If the requirements described above aredetermined to be satisfied, the mode is switched from the “held mode” tothe “placed mode” (Step S403).

In contrast, if it is determined that a hand is coming closer to theimage display apparatus 1 to hold the image display apparatus 1, andthereafter if it is determined that the image display apparatus 1 isheld in the hand, the “placed mode” may be switched to the “held mode”.Specifically, as illustrated in FIG. 17, the mode switching unit 19determines whether a hand is coming closer to the image displayapparatus 1 on the basis of the detection result outputted from anon-illustrated camera (Step S501). Thereafter, if it is determined thata hand is coming closer to the image display apparatus 1, it isdetermined whether the hand coming closer to the image display apparatus1 will hold the image display apparatus 1 (Step S502). Thereafter, if itis determined that the hand will hold the image display apparatus 1, thetouch panel 3 is brought into the state irresponsive to operations suchas flick operations and pointing operations. Thereafter, it isdetermined whether a palm or fingers are in contact with the imagedisplay apparatus 1 on the basis of the detection result outputted fromthe touch panel 3 (Step S503). Thereafter, if it is determined that apalm or fingers are in contact with the image display apparatus 1, it isdetermined in which direction the image display apparatus 1 is moving onthe basis of the detection result outputted from the motion detector 4(Step S504). Then, if it is determined that the image display apparatus1 is moving in any direction, the mode is switched from the “placedmode” to the “held mode” (Step S505).

Further, if it is determined that an acceleration rate greater than orequal to a predetermined value has been applied to the image displayapparatus 1, for example, the “held mode” may be switched to the “shakenmode”. Specifically, as illustrated in FIG. 18, the mode switching unit19 determines whether the image display apparatus 1 has been shaken atan acceleration rate greater than or equal to the predetermined valuepreliminarily determined on the basis of the detection result outputtedfrom the motion detector 4 (Step S601). Thereafter, if it is determinedthat the image display apparatus 1 has been shaken, the image displayapparatus 1 is brought into a state where operations for shaking ortilting the image display apparatus 1 are acceptable (Step S602). If itis determined that these operations have been performed in such a state,the three-dimensional image is changed so that the three-dimensionalobject 15 deviates from the central portion of the space 14 of thedisplay 2 and moves in association with the motion of the display 2itself (Step S603). In contrast, if it is not determined that theseoperations have been performed, the three-dimensional image is changedso that the three-dimensional object 15 moving at the bottom portion ofthe space 14 in accordance with a predetermined physical law isdisplayed (Step S603). Thereafter, it is determined that predeterminedtime (e.g., one minute) preliminarily determined has been elapsed sincethe bottom face of the pedestal 8 of the image display apparatus 1 wasplaced on a flat surface, the three-dimensional image is changed so thatthe three-dimensional object 15 returns to the central portion of thespace 14 of the display 2 (Step S603). The mode is then switched fromthe “held mode” to the “placed mode” (Step S604).

Further, if it is determined that the display 2 has not been moved by anexternal force, i.e., no acceleration rate has not been detected, for apreliminarily determined predetermined time or longer while the imagedisplay apparatus 1 is in the “shaken mode”, the “shaken mode” may beswitched to the “held mode”. Further, the mode of the image displayapparatus 1 may be selected using another device such as a smartphone,for example. Further, the image display apparatus 1 may be provided withthree mode switch buttons respectively corresponding to the “placedmode”, the “held mode”, and the “shaken mode”, for example. When any ofthe three mode switch buttons is pressed down, it may be determined thatthe mode corresponding to the mode switch button pressed down has beenselected.

(11) Further, although the “placed mode”, the “held mode”, and the“shaken mode” are exemplified as the modes of the image displayapparatus 1 in the embodiment, another configuration may be employed.For example, the image display apparatus 1 may be switched to a “sleepmode” in which displaying of the three-dimensional image is restrictedto save power or to protect user's privacy when a preliminarilydetermined predetermined time has been elapsed since the last operation(e.g., operation for holding up shaking the image display apparatus 1)was performed on the image display apparatus 1. For example, in a casewhere the three-dimensional object 15 is the tono-sama penguincharacter, the three-dimensional image representing the character in asleeping state may be displayed on the display 2 in the “sleep mode”.Alternatively, three-dimensional image representing animation such as ascreen saver may be displayed on the display 2, for example. If it isdetermined that the user is approaching the image display apparatus 1 orthat an operation has been performed on the image display apparatus 1 inthe “sleep mode”, the image display apparatus 1 may be returned to themode immediately before the switching to the “sleep mode”.

It is to be noted that the technology may have the followingconfigurations.

(1) An image display apparatus including:

-   -   a display displaying a three-dimensional image in such a manner        that the three-dimensional object looks as if being in a space        defined by a member constituting an external surface and that        the three-dimensional object is visible from multiple directions        around the display;    -   a motion detector detecting a motion of the display itself        caused by an external force;    -   a motion calculation unit calculating a motion of the        three-dimensional object caused by the motion of the display        itself on the basis of the motion detected by the motion        detector on the assumption that the three-dimensional object is        actually present in the space;    -   a display control unit changing the three-dimensional image        displayed on the display on the basis of a result of calculation        by the motion calculation unit;    -   a force sense presentation unit presenting a sense of force to a        user of an own apparatus; and a force sense control unit causing        the force sense presentation unit to present the sense of force        on the basis of the result of calculation by the motion        calculation unit.

(2) The image display apparatus according to (1) described above, inwhich

-   -   the display control unit changes the three-dimensional image on        the basis of the result of calculation by the motion calculation        unit to display the motion of the three-dimensional object        caused by the motion of the display itself, and    -   the force sense control unit causes the force sense presentation        unit to display the sense of force on the basis of the result of        calculation by the motion calculation unit on the assumption        that the three-dimensional object is actually present in the        space to make the user feel a vibration supposed to be generated        by contact of the three-dimensional object with the member        constituting the external surface.

(3) The image display apparatus according to (1) or (2) described above,in which

-   -   substance data indicating at least one of a mass, a center of        gravity, a density, a volume, a Young's modulus, a Poisson's        ratio, a vibration damping rate, a viscosity, or an outer shape        is set to the three-dimensional object, and    -   the motion calculation unit calculates the motion of the        three-dimensional object on the basis of the substance data and        the motion detected by the motion detector in accordance with a        predetermined physical low.

(4) The image display apparatus according to any one of (1) to (3)described above, further including an input operation detector detectingan input operation performed by the user, in which

-   -   the display control unit further includes a display operation        unit that changes the three-dimensional image displayed on the        display on the basis of a result of detection of the input        operation.

(5) The image display apparatus according to (4) described above, inwhich the input operation detector is at least one of a touch panelprovided on the external surface of the display, a microphone picking upsurrounding sounds of the display, a camera capturing surrounding imagesof the display, or a distance image sensor capturing surroundingdistance images of the display.

(6) The image display apparatus according to (5) described above, inwhich

-   -   the input operation detector is the touch panel, and    -   the display operation unit detects a position of the touch panel        in contact with a finger, and changes the three-dimensional        image displayed on the display on the basis of the position        detected. (7) The image display apparatus according to any one        of (4) to (6) described above, in which    -   a single piece of the input operation detector has a plurality        of operation methods, and    -   the display operation unit changes the three-dimensional image        displayed on the display only on the basis of the result of        detection of an input operation performed by one of the        plurality of operation methods when the display is held in a        hand. (8) The image display apparatus according to (7) described        above, in which the display operation unit prohibits the        three-dimensional image from changing on the basis of the result        of detection detected by the input operation detector when the        display is held in the hand.

(9) The image display apparatus according to any one of (4) to (6)described above, in which

-   -   a single piece of the input operation detector has a plurality        of operation methods,    -   when input operations performed by the plurality of operation        methods are detected, the display operation unit changes the        three-dimensional image displayed on the display only on the        basis of a result of detection of an input operation performed        by a method with a highest priority out of the input operations        detected, and priorities assigned to the operation methods        differ between when the display is shaken and when the display        is not shaken.

REFERENCE SIGNS LIST

1 . . . image display apparatus, 2 . . . display, 3 . . . touch panel, 4. . . motion detector, 5 . . . sound generator, 6 . . . point, 6 . . .force sense presentation unit, 7 . . . point, 7 . . . controller, 8 . .. pedestal, 9 . . . screen, 10 . . . reflecting mirror, 11 . . . opticalaxis, 12 . . . emitter, 13 . . . image light, 14 . . . space, 15 . . .three-dimensional object, 16 . . . storage device, 17 . . . processor,18 . . . display control unit, 19 . . . mode switching unit, 20 . . .motion calculation unit, 21 . . . force sense control unit, 22 . . .sound control unit, 23 . . . display operation unit

1. An image display apparatus comprising: a display displaying athree-dimensional image in such a manner that the three-dimensionalobject looks as if being in a space defined by a member constituting anexternal surface and that the three-dimensional object is visible frommultiple directions around the display; a motion detector detecting amotion of the display itself caused by an external force; a motioncalculation unit calculating a motion of the three-dimensional objectcaused by the motion of the display itself on a basis of the motiondetected by the motion detector on an assumption that thethree-dimensional object is actually present in the space; a displaycontrol unit changing the three-dimensional image displayed on thedisplay on a basis of a result of calculation by the motion calculationunit; a force sense presentation unit presenting a sense of force to auser of an own apparatus; and a force sense control unit causing theforce sense presentation unit to present the sense of force on a basisof the result of calculation by the motion calculation unit.
 2. Theimage display apparatus according to claim 1, wherein the displaycontrol unit changes the three-dimensional image on the basis of theresult of calculation by the motion calculation unit to display themotion of the three-dimensional object caused by the motion of thedisplay itself, and the force sense control unit causes the force sensepresentation unit to display the sense of force on the basis of theresult of calculation by the motion calculation unit on the assumptionthat the three-dimensional object is actually present in the space tomake the user feel a vibration supposed to be generated by contact ofthe three-dimensional object with the member constituting the externalsurface.
 3. The image display apparatus according to claim 1, whereinsubstance data indicating at least one of a mass, a center of gravity, adensity, a volume, a Young's modulus, a Poisson's ratio, a vibrationdamping rate, a viscosity, or an outer shape is set to thethree-dimensional object, and the motion calculation unit calculates themotion of the three-dimensional object on a basis of the substance dataand the motion detected by the motion detector in accordance with apredetermined physical low.
 4. The image display apparatus according toclaim 1, further comprising an input operation detector detecting aninput operation performed by the user, wherein the display control unitfurther includes a display operation unit that changes thethree-dimensional image displayed on the display on a basis of a resultof detection of the input operation.
 5. The image display apparatusaccording to claim 4, wherein the input operation detector comprises atleast one of a touch panel provided on the external surface of thedisplay, a microphone picking up surrounding sounds of the display, acamera capturing surrounding images of the display, or a distance imagesensor capturing surrounding distance images of the display.
 6. Theimage display apparatus according to claim 5, wherein the inputoperation detector comprises the touch panel, and the display operationunit detects a position of the touch panel in contact with a finger, andchanges the three-dimensional image displayed on the display on a basisof the position detected.
 7. The image display apparatus according toclaim 4, wherein a single piece of the input operation detector has aplurality of operation methods, and the display operation unit changesthe three-dimensional image displayed on the display only on a basis ofa result of detection of an input operation performed by one of theplurality of operation methods when the display is held in a hand. 8.The image display apparatus according to claim 7, wherein the displayoperation unit prohibits the three-dimensional image from changing on abasis of a result of detection detected by the input operation detectorwhen the display is held in the hand.
 9. The image display apparatusaccording to claim 4, wherein a single piece of the input operationdetector has a plurality of operation methods, when input operationsperformed by the plurality of operation methods are detected, thedisplay operation unit changes the three-dimensional image displayed onthe display only on a basis of a result of detection of an inputoperation performed by a method with a highest priority out of the inputoperations detected, and priorities assigned to the operation methodsdiffer between when the display is shaken and when the display is notshaken.